Clinical platelet count, antibody-binding characteristics, and bone marrow samples. The graph shows the time course of platelet counts in relation to 2 exposures to eptifibatide in a 67-year-old male patient with acute coronary syndrome (body weight 80 kg; compensated renal impairment). Inset 1 represents the increased binding of IgG, when normal platelets were incubated with patient serum in the presence of eptifibatide (1 μg/mL) but not in the presence of patient serum and buffer, as assessed by flow cytometry. Inset 2 represents a representative example of the bone marrow obtained on day 4 after start of thrombocytopenia. The left panel represents, in an overview, the reduced megakaryocyte count at a 10-fold magnification. Higher magnification (right panel, 60-fold magnification) reveals the young phenotype of the megakaryocyte marked with an arrow from overview microscopy at the left panel. Smears were stained by May-Gruenwald and Giemsa stain (Merck) following standard protocol (microscope: Olympus BX50F; objectives: UPlan FL 10×/0.30; PlanApo 60×/1.40 with oil; camera: ColorView Illu; software: AnalySIS Five; all Olympus Europe).